1. Field of the Invention
The present invention relates to a method for producing a new allyl compound different from an allyl starting material compound by reacting the allyl starting material compound with a nucleophilic agent in the presence of a catalyst comprising a transition metal compound and a phosphite compound, and an allyl compound produced thereby.
2. Prior Arts
Various kinds of new allyl compounds can be synthesized by carrying out a catalytic reaction using a transition metal compound and using an allyl compound as a starting material. This reaction proceeds as illustrated in the following reaction formula, wherein an allyl starting material compound having an eliminating group X is Π-coordinated and oxidatively added to a transition metal compound to form a Π-allyl complex having three carbons of the allyl part bonded to a metal and the terminal allyl carbon of the Π-allyl complex is attacked by a nucleophilic agent expressed by Nu—H or Nu−.

The synthesizing reaction of an allyl compound is generally fully described in “Palladium Reagents and Catalysts—Innovations in Organic Synthesis—” published by John Wiley & Sons Company, and various products in a form of allylated nucleophilic agent can be obtained by electing a kind of a nucleophilic agent in the reaction.
For example, when the nucleophilic agent is malonic acid diester, malonic acid diester having an allyl group bonded is formed (allylic alkylation reaction), and when the nucleophilic agent is a primary or secondary amine, allyl amines are formed (allylic amination reaction) and when the nucleophilic agent is phenol or carboxylic acid, allyl phenyl ether or carboxylic acid allyl ester are respectively formed.
On the other hand, as a transition metal compound for a catalyst, a palladium compound is most famous, but a catalytic reaction of an allyl compound with a ruthenium compound, a nickel compound, an iridium compound or the like is also known. Further, there have been developed various ligands to improve a catalytic activity, a regioselectivity of reaction or an enantioselectivity by being coordinated to such transition metal compounds.
When carrying out allylation reaction with the above-mentioned catalyst on an industrial scale, it is strongly demanded to improve a catalyst reactivity in order to reduce a catalyst cost by reducing an amount of catalyst used or to reduce a manufacturing cost by making a reactor size smaller. Further, in order to reduce the cost of a catalyst itself, it is necessary to reduce a production cost of a ligand used. From this viewpoint, such a bidentate coordinated phosphite ligand as described in “Chem. Commun., 2001, p 1132” and “J. Org. Chem., 2001, 66, p 8867” is not suitable for a high temperature reaction achieving a high catalyst activity since its crosslinking part comprises glucose and a ligand does not have a satisfactory thermal stability.
Also, recently reported WO2002/040491 publication discloses a reaction of an allyl ester starting material compound with a carbon nucleophilic agent (allylic alkylation reaction) or with a nitrogen nucleophilic agent (allylic amination reaction) by using a bidentate coordinated phosphite ligand having an axial asymmetry at the biphenol part of crosslinking portion, but does not illustrate an actual example of allylation reaction using the bidentate coordinated phosphite ligand and does not disclose a structure of the phosphite compound to be suitably used for the allylation reaction.
When carrying out allylation reaction using the above-mentioned catalyst on an industrial scale, it is strongly demanded to improve a reactivity in order to reduce an amount of expensive palladium used, which is a noble metal, or to make a reactor size smaller, thereby reducing a manufacturing cost. As a method for improving the reactivity, there is a method for having a counter cation of a nucleophilic agent present in the reaction system. As its effect, a nucleophilic agent forming a pair or a coexistent state with such a counter cation increases its nucleophilic attacking force, thereby improving the reactivity.
As some examples, a reaction of cyclopentadiene monoxide and an acetic acid anion is reported in “Organic Syntheses, 1998, 67, p 114”, and in order to improve the reactivity, a sodium ion is used as a counter cation for acetic anion in this reaction. However, when such an alkali metal is a counter cation, +1 valent charge is concentrated on one small metal ion, and accordingly there is a tendency of forming a strong ion pair with a nucleophilic agent of a counter anion. Consequently, the attacking force of such a nucleophilic agent is not sufficiently high.
For example, it is reported in “Tetrahedron Lett., 1998, 39, p 5439” that an allyl starting material compound and a formic acid anion are reacted by using a palladium catalyst comprising a triisopropyl phosphite ligand of trialkyl type monodentate phosphite in the presence of ammonium comprising triethylamine having a proton coordinate-bonded, but this reaction is a reaction different from a reaction of an ordinary allyl starting material compound and a nucleophilic agent. That is, the formic acid anion does not form allyl formate by attacking a Π-allyl complex as an intermediate but is coordinated to palladium, and carbon dioxide is eliminated and a hydride formed as this result reacts with the Π-allyl complex to provide a product of a structure having the allyl starting material reduced.
As mentioned above, in order to produce various allyl compounds by reaction of an allyl starting material compound and a nucleophilic agent on an industrial scale, it is important to reduce a catalyst cost. As a method for reducing the catalyst cost, there are provided a method for reducing an amount of a catalyst used, a method for reducing a ligand cost by using a cheap ligand, a method for recycling a ligand by using a stable ligand and the like, but when using a phosphine type ligand which is relatively hardly synthesized, as a ligand, or when using a bidentate ligand having an axial asymmetry or a complicated bidentate ligand such as P—N, P—O, P—S or N—S, a manufacturing cost of the ligand becomes high. Also, in a case of a bidentate phosphite ligand which can be relatively easily synthesized, if a carbon atom of P—O—C bond at the crosslinking part is a sp3 carbon of an alkyl group, a satisfactory thermal stability can not be obtained and it is difficult to be used for carrying out a highly active reaction at a high temperature. Accordingly, there has been demanded development of a new catalyst system using a ligand having a satisfactory thermal stability and achieving a high activity, which can be easily prepared.
The present invention has been made in order to solve the above-mentioned problems. Thus, an object of the present invention is to provide a method for producing an industrially advantageous allyl compound by using a new catalyst system having an excellent thermal stability and achieving a high activity, which can be easily prepared, thereby efficiently producing various allyl compounds.
The present inventors have intensively studied to develop a catalyst system capable of efficiently proceeding an intermolecular reaction of a nucleophilic agent and various allyl starting material compounds, and have discovered that a satisfactory catalyst having a high activity can be obtained by combining a transition metal compound of Group 8 to Group 10 of the Periodic Table with a specific bidentate phosphite ligand having a branched alkyl group at the ortho position of an aryl group and a carbon atom of P—O—C bond at a crosslinking part, the carbon atom of which is a sp2 carbon derived from an aryl group. The present invention has been accomplished on the basis of this discovery.